api: handle nil pointer dereference in rest endpoints

When `?all=garbage` is passed to an API endpoint schema validation fails
and err is nil. Wrapf uses err to create an error message causing a nil
pointer dereference.

Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>

3 files changed, 18 insertions, 3 deletions

diff --git a/pkg/api/handlers/compat/containers.go b/pkg/api/handlers/compat/containers.go
index 26e1bf00b..a15fdb553 100644
--- a/pkg/api/handlers/compat/containers.go
+++ b/pkg/api/handlers/compat/containers.go
@@ -104,8 +104,12 @@ func ListContainers(w http.ResponseWriter, r *http.Request) {
 	}
 
 	filterMap, err := util.PrepareFilters(r)
+	if err != nil {
+		utils.Error(w, "Something went wrong.", http.StatusInternalServerError, errors.Wrapf(err, "failed to decode filter parameters for %s", r.URL.String()))
+		return
+	}
 
-	if dErr := decoder.Decode(&query, r.URL.Query()); dErr != nil || err != nil {
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
 		utils.Error(w, "Something went wrong.", http.StatusInternalServerError, errors.Wrapf(err, "failed to parse parameters for %s", r.URL.String()))
 		return
 	}
diff --git a/pkg/api/handlers/libpod/containers.go b/pkg/api/handlers/libpod/containers.go
index 4639093f2..343c0d0b3 100644
--- a/pkg/api/handlers/libpod/containers.go
+++ b/pkg/api/handlers/libpod/containers.go
@@ -73,8 +73,13 @@ func ListContainers(w http.ResponseWriter, r *http.Request) {
 	}
 
 	filterMap, err := util.PrepareFilters(r)
+	if err != nil {
+		utils.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError,
+			errors.Wrapf(err, "failed to decode filter parameters for %s", r.URL.String()))
+		return
+	}
 
-	if dErr := decoder.Decode(&query, r.URL.Query()); dErr != nil || err != nil {
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
 		utils.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError,
 			errors.Wrapf(err, "failed to parse parameters for %s", r.URL.String()))
 		return
diff --git a/pkg/api/handlers/libpod/images.go b/pkg/api/handlers/libpod/images.go
index 72093c492..b4f08a746 100644
--- a/pkg/api/handlers/libpod/images.go
+++ b/pkg/api/handlers/libpod/images.go
@@ -156,8 +156,14 @@ func PruneImages(w http.ResponseWriter, r *http.Request) {
 	}
 
 	filterMap, err := util.PrepareFilters(r)
+	if err != nil {
+		utils.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError,
+			errors.
+				Wrapf(err, "failed to decode filter parameters for %s", r.URL.String()))
+		return
+	}
 
-	if dErr := decoder.Decode(&query, r.URL.Query()); dErr != nil || err != nil {
+	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
 		utils.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError,
 			errors.
 				Wrapf(err, "failed to parse parameters for %s", r.URL.String()))